1. Field of the Invention
Embodiments of the invention relate to medical imaging systems and, more particularly, to multiplane medical imaging systems capable of producing radiographic images in several planes and allowing the examination of an area of interest in several planes.
2. Description of Related Art
Imaging systems usually comprise an X-ray machine comprising an X-ray tube and an X-ray detector placed opposite the X-ray tube in the direction of emission of X-rays. The tube and the detector are usually placed on two mutually opposite ends of an arm.
Such systems are used for angiographic examinations for diagnostic or interventional purposes. During these examinations, it is necessary to produce radiographs by X-rays of an area of interest in the body of a patient. For this purpose, after the patient has been laid out on an examination table, the X-ray tube and the detector are brought to face the area to be radiographed.
A known X-ray system that is fixed to the floor comprises an arm that supports the X-ray tube and the detector, the arm comprising several degrees of freedom that makes it possible to position the X-ray beam facing an area of interest.
This type of system, however, has a major drawback relating to the fact that the radiography need is only necessary during a limited time of the procedure. Meanwhile, access to the patient must be given priority. The systems can therefore not be moved away from the examination table when they are not in use. In particular, the transfer and the placement of the patient on the examination table are hampered by the presence of this cumbersome system. It has therefore been proposed to mount the X-ray machine on a mobile device mounted on wheels driven by motors controlled automatically under the control of a navigation system.
There are also X-ray systems called “surgical mobile” units that can be moved manually. These systems are mounted on a carriage that contains batteries used to supply the X-ray tube with power. This type of system is not suitable for angiographic examinations because the power delivered by the X-ray tube is not sufficient to obtain adequate image quality and, in particular, adequate contrast.
Moreover, this type of mobile X-ray system does not allow complex angulations because the diameter of the arm supporting the tube and the detector is not big enough. Similarly, these mobile X-ray systems do not achieve sufficient rotation speeds to allow good quality, three-dimensional image reconstructions. Finally, even though the weight of such a system is half as much as that of an X-ray machine designed for angiography, it remains very difficult to move because of its relatively large dimensions and weight, which can be up to about 300 kg (about 660 lbs).
Finally, X-ray systems for angiography that are suspended from the ceiling and can be moved on guiderails via a mobile carriage driven, for example, with the aid of an electric motor, are known.
During the implementation of angiographic examinations, it may be necessary to use multiplane medical imaging systems, for example biplane systems, that are capable of forming images of a vessel in several planes in order to visualize the vessels in these different planes, most frequently perpendicular planes.
Biplane medical imaging systems, therefore, comprise two X-ray machines each capable of forming an image in one plane. These machines are, for example, mounted either on the floor or on the ceiling.
A multiplane medical imaging system has been described which comprises, for example, a first X-ray machine mounted on a robot fixed to the floor, and a second X-ray machine supported by a second robot that can move relative to the floor or is mounted to slide on rails attached to the ceiling.
In this type of medical imaging system, the X-ray machines are relatively bulky so that, during the radiological examination, access to the patient on an examination table is considerably limited.
This access limitation is due to the location of the first X-ray machine. Being fixed to the floor in the vicinity of the frontal zone of an examination or operating table on which the patient is located, considerably limits access to the patient.
Moreover, the radiographic requirements for certain examinations or interventions are necessary only for a limited period of the procedure. Meanwhile, it is access to the patient or to the examination table that must be given priority, so it is desirable that the X-ray machines are both moved away from the table, for example, during the transfer and the positioning of the patient on the table.
Finally, in certain types of examination for interventional purposes, it may be essential to keep the examination table, itself mobile, in a fixed position in order to prevent moving the patient. In such a configuration, the X-ray machines of the multiplane imaging system are the only items to be moved and brought to face the area of interest to be radiographed. Here again, fixing the robot to the floor is likely to limit the ability to move the X-ray machine.
In view of the foregoing, there exists a need to have a multiplane medical imaging system and, notably, a biplane system that is capable of increasing the degrees of freedom of the X-ray machines by increasing their ability for movement.